If you miss watching him paint little happy trees, then you can always make your own Bob Ross doll to paint tiny masterpieces on your desktop. At least, that's what Allison Hoffman of Crafty is Cool did.

The painting isn't Ross-like. The way the trees and foliage look seems too thick and detailed; and the mountain and clouds, Ross never painted them that way. Even the water looks odd. At least the forest in the background resembled his style.

Or perhaps his style had changed in the later seasons (I only watched the first few seasons).